I have below 50%mark in 12th,I have completed Be-tech in electronics ,Then I start my career a small company ,I have 3 year experience in my field,can I get job MNC like TCS,CTS.?

#-Link-Snipped-# - The simplest way to check this is to go through the target job description and find out if it mentions anything about the education criteria. If it does not, do not mention your 12th or Graduation marks in your resume.

If you performed well in your graduation, feel free to mention your final year or aggregate marks OR GPA score in your resume; otherwise it does not matter. 

Have you tried applying to any job with the big companies? Also, in which domain are you experienced? 

What should be our grade to take part in placement activity for a particular company?